Problem: Brian irons $\dfrac29$ of his shirt in $3\dfrac35$ minutes. Brian irons at a constant rate. At this rate, how much of his shirt does he iron each minute?
Answer: To find shirts per minute, we divide shirts by minutes. $\phantom{=}\dfrac{~~~ \dfrac29 \text{ shirt}~~~}{3\dfrac35 \text{ minutes}}$ $ = \dfrac29 \div 3\dfrac35 $ $ = \dfrac{2}9 \div \dfrac{18}5 $ $ = \dfrac{2}{9} \cdot \dfrac5{18} $ $ =\dfrac{10}{162} $ $ =\dfrac{5}{81}$ shirt per minute $ $ Each minute, Brian irons $\dfrac{5}{81}$ of his shirt.